Add CLI option support to config fixture

oslo.config.fixture.Config has register_opt() and register_opts() but
not register_cli_opt() and register_cli_opts().

Change-Id: I8a1582dc0deb0230eb02b0894a49398f333375fe

oslo/config/fixture.py

@@ -84,3 +84,35 @@ class Config(fixtures.Fixture):
         """
         for opt in opts:
             self.register_opt(opt, group=group)
+
+    def register_cli_opt(self, opt, group=None):
+        """Register a single CLI option for the test run.
+
+        Options registered in this manner will automatically be unregistered
+        during cleanup.
+
+        If a `group` argument is supplied, it will register the new option
+        to that group, otherwise the option is registered to the ``default``
+        group.
+
+        CLI options must be registered before the command line and config files
+        are parsed. This is to ensure that all CLI options are shown in --help
+        and option validation works as expected.
+        """
+        self.conf.register_cli_opt(opt, group=group)
+        self._registered_config_opts.setdefault(group, set()).add(opt)
+
+    def register_cli_opts(self, opts, group=None):
+        """Register multiple CLI options for the test run.
+
+        This works in the same manner as register_opt() but takes a list of
+        options as the first argument. All arguments will be registered to the
+        same group if the ``group`` argument is supplied, otherwise all options
+        will be registered to the ``default`` group.
+
+        CLI options must be registered before the command line and config files
+        are parsed. This is to ensure that all CLI options are shown in --help
+        and option validation works as expected.
+        """
+        for opt in opts:
+            self.register_cli_opt(opt, group=group)

tests/test_fixture.py

@@ -28,8 +28,6 @@ class ConfigTestCase(base.BaseTestCase):
         super(ConfigTestCase, self).setUp()
         self.config_fixture = self.useFixture(config.Config(conf))
         self.config = self.config_fixture.config
-        self.register_opt = self.config_fixture.register_opt
-        self.register_opts = self.config_fixture.register_opts
         self.config_fixture.register_opt(cfg.StrOpt(
             'testing_option', default='initial_value'))
 
@@ -55,7 +53,7 @@ class ConfigTestCase(base.BaseTestCase):
     def test_register_options(self):
         opt1 = cfg.StrOpt('first_test_opt', default='initial_value_1')
         opt2 = cfg.StrOpt('second_test_opt', default='initial_value_2')
-        self.register_opts([opt1, opt2])
+        self.config_fixture.register_opts([opt1, opt2])
         self.assertEqual(conf.get('first_test_opt'), opt1.default)
         self.assertEqual(conf.get('second_test_opt'), opt2.default)
 
@@ -66,3 +64,24 @@ class ConfigTestCase(base.BaseTestCase):
                          opt.default)
         self.config_fixture.cleanUp()
         self.assertRaises(cfg.NoSuchOptError, conf.get, 'new_test_opt')
+
+    def test_register_cli_option(self):
+        opt = cfg.StrOpt('new_test_opt', default='initial_value')
+        self.config_fixture.register_cli_opt(opt)
+        self.assertEqual(conf.get('new_test_opt'),
+                         opt.default)
+
+    def test_register_cli_options(self):
+        opt1 = cfg.StrOpt('first_test_opt', default='initial_value_1')
+        opt2 = cfg.StrOpt('second_test_opt', default='initial_value_2')
+        self.config_fixture.register_cli_opts([opt1, opt2])
+        self.assertEqual(conf.get('first_test_opt'), opt1.default)
+        self.assertEqual(conf.get('second_test_opt'), opt2.default)
+
+    def test_cleanup_unregister_cli_option(self):
+        opt = cfg.StrOpt('new_test_opt', default='initial_value')
+        self.config_fixture.register_cli_opt(opt)
+        self.assertEqual(conf.get('new_test_opt'),
+                         opt.default)
+        self.config_fixture.cleanUp()
+        self.assertRaises(cfg.NoSuchOptError, conf.get, 'new_test_opt')